What makes us love certain foods and abhor others? Those wondering what insights the former deputy prime minister might have into the field of chemosensory perception can rest assured that this John Prescott was until last year an associate professor of psychology at the University of Newcastle, Australia.

Prescott runs a consultancy "in the area of food perceptions and preferences", and Taste Matters offers both a detailed analysis of that area and a broader examination of the psychology of eating. For example, he looks at why young children can be reluctant to try new foods, and what strategies parents might adopt in response, before expanding his inquiry to cover cravings, aversions, the external cues and psychological motivations that prompt us to eat, and why, once we've started, it can be so difficult to stop. While rigorously supported by the scientific evidence, Prescott's method makes concessions to the lay reader in its recourse to anecdote, trivia and, less engagingly, a rather professorial idea of light relief (chapter subheadings include "Broccoli... Be Very Afraid!").

Nonetheless, this hybrid approach frequently makes for fascinating reading. In his chapter on aversions, Prescott asks us to imagine feeling a bit piquey, eating something nice to cheer ourselves up, being violently sick, then never being able to bear the sight or smell of it again. "Instinctively, your brain has linked the gastrointestinal upset with the most likely environmental cause on offer, namely the food that you had just consumed."

But this "learning process" can be hoodwinked. Prescott tells the story of a friend of his who, knocking back the whiskies on a rough ferry crossing, had the foresight to chase them with a glass of milk, a lifetime of drinking his coffee black being "a small price to pay for a continued preference for his national drink". On the same principle, some cancer patients are given an unfamiliar-tasting sweet between a chemotherapy session and the meal immediately preceding it. This way the aversion is developed for the nutritionally worthless sweet – the "scapegoat" – as opposed to the food the patient needs to aid them in their recovery.

Anyone versed in the literature of dieting, nutrition or childcare may find some of Prescott's broader findings familiar. But the details of the studies that support them are enlightening, as is the glimpse they give of the work of psychologists in the relatively new field of "food preference". For the chef or home cook, Taste Matters contains little in the way of directly practicable information, but there's certainly food for thought here, particularly for the menu designer, nutritionist or thwarted slimmer. Studies have indicated that we are programmed to crave high-energy (ie sweet, high-fat) foods, and that most of us, when we succumb to these cravings, find fullness an easily ignorable incentive to stop.

Not that suppressing these cravings is much help, either. Something psychologists call the "response deprivation hypothesis" proposes that "restriction itself increases the reward value of whatever is restricted". In other words, deny yourself that custard slice and its resistibility, next time you're passing the cake shop, will be that little bit diminished. Desire grows by what it doesn't feed on.

In this light, the wonder is that there are so many of us who aren't overweight. Of all "taste matters", weight gain and its related diseases are perhaps the most pressing, and it's a shortcoming of Prescott's book that he largely ducks the question of how to address them. Prescott believes that the notion of "unhealthy food" is problematic. In essence, there are no unhealthy foods – only unhealthy diets. The trick is to keep your consumption of fatty, salty, sugary, additive-laden junk within reasonable limits. Conversely, it's perfectly possible to overindulge in what culture constructs as "good". "Carrots," Prescott writes, "fit neatly into the 'healthy' basket until too many are eaten, at which point carotene poisoning can occur."

Well, fine – except it's just been demonstrated that excessive consumption of high-energy foods is something we find extremely difficult to resist. And carotene poisoning? Ah yes, that growing strain on NHS resources: the orange face epidemic. Prescott is right to question the "whiff of moral judgment in many purely nutritional approaches to considering the foods we eat", but at times his position on what might help or harm us is relativistic to the point of unhelpfulness. For the reader contemplating his second cheeseburger-crusted pizza, with double chocolate cake to follow, the implication is stark. You're on your own, sunshine.